Wireless neurostimulators

ABSTRACT

An implant is implanted into a tissue of a subject. The implant includes a circuitry unit that houses circuitry, and one or more outwardly-facing electrodes that are electrically coupled to the circuitry. The circuitry unit is shaped to define a height that is smaller than (i) a longest length, and (ii) a longest width of the circuitry unit. The implant is oriented with respect to the tissue, such that: (a) the height of the circuitry unit is disposed along a superficial-to-deep axis with respect to skin of the subject, (b) the implant is positioned to stimulate a nerve underlying the implant, and (c) the implant is positioned in a manner that inhibits electrical conduction from the outwardly-facing electrodes into skin of the subject. Other embodiments are also described.

CROSS-REFERENCES TO RELATED APPLICATIONS

The present application (1) claims priority from (a) U.S. 61/591,024 toGross, filed Jan. 26, 2012, and (b) U.S. 61/662,073 to Gross et al.,filed Jun. 20, 2012, and (2) is related to (a) US 2011/0301670 to Gross,filed Jun. 8, 2010, and (b) U.S. Ser. No. 13/528,433 to Gross, filedJun. 20, 2012, all of which are assigned to the assignee of the presentapplication, and all of which are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates generally to medical devices, andspecifically to apparatus and methods for neurostimulation.

BACKGROUND

Neurological disorders affect the nerves, muscles or the brain. Manyneurological disorders reduce or eliminate voluntary recruitment ofmuscles, which may result in loss of ability to perform motor tasks orto maintain systems that depend on muscle activity for their function.Other disorders may cause pain to adjacent tissues.

Neurostimulation is a clinical tool used to treat various neurologicaldisorders. This technique involves modulation of the nervous system byelectrically activating fibers in the body.

SUMMARY OF APPLICATIONS

For some applications of the present invention, a system for wirelessneurostimulation comprises a circuitry unit, coupled to at least twoelectrodes. According to one application of the present invention, oneelectrode is disposed on an outer surface of the circuitry unit, whereasa second electrode is coupled to a nerve cuff. According to anotherapplication of the present invention, the at least two electrodes arecoupled to the nerve cuff (or to two or more nerve cuffs). Typically,the circuitry unit and nerve cuff are coupled by a lead.

Typically, the circuitry unit comprises circuitry for receiving andprocessing energy for driving the electrodes, and this energy isreceived from a site outside of the circuitry unit. For example, thesite may be inside, or outside, of the subject's body.

For some applications of the present invention, the circuitry unit iscoupled via leads to two nerve cuffs. Typically, each nerve cuffcomprises one or more electrodes.

For some applications of the present invention, the circuitry unit iscoupled via a lead to an antenna.

For some applications of the present invention, the circuitry unit iscoupled via a lead to an array of microelectrodes. For some applicationsof the present invention, the microelectrodes are disposed on thecircuitry unit itself.

There is therefore provided, in accordance with an application of thepresent invention, apparatus for applying a treatment to at least onetissue of a subject, the apparatus including: a transmitting unit,configured to transmit a wireless power signal; and a first implant anda second implant, each of the implants being configured to receive thepower signal and to apply the treatment asynchronously to each other, inresponse to the power signal.

In an application, the first implant includes a plurality of firstimplants, the first implants being configured to apply the treatmentsynchronously with respect to each other, in response to the powersignal.

In an application, at least one of the implants includes asubcutaneously-implantable implant.

In an application, the implants are configured to receive power from thepower signal.

In an application, the first implant does not include a power supplythat is able to continuously power the first implant for a periodgreater than one minute.

In an application, the second implant does not include a power supplythat is able to continuously power the second implant for a periodgreater than one minute.

In an application:

-   -   the first implant is configured to receive the power signal, and        to apply the treatment after a first duration following        receiving the power signal, and    -   the second implant is configured to receive the power signal,        and to apply the treatment after a second duration following        receiving the power signal, the second duration being longer        than the first duration.

In an application:

-   -   the transmitting unit is configured to transmit a plurality of        wireless power signals, including at least first and second        wireless power signals,    -   the first implant is configured to receive power from the first        power signal, and    -   the second implant is configured to receive power from the        second power signal.

In an application, the transmitting unit is configured to transmit thefirst and second power signals asynchronously.

In an application, the first implant is configured to apply thetreatment in response to the first power signal, and the second implantis configured to apply the treatment in response to the second powersignal.

In an application:

-   -   the transmitting unit is configured to configure the first and        second power signals to have respective first and second        characteristics that differ from one another,    -   the first implant is configured to receive power from the first        power signal, in response to an effect of the first        characteristic on the first implant, and    -   the second implant is configured to receive power from the        second power signal, in response to an effect of the second        characteristic on the second implant.

In an application:

-   -   the first and second characteristics include respective first        and second frequencies, and    -   the transmitting unit is configured to configure the first and        second power signals to have the respective first and second        frequencies.

In an application:

-   -   the first and second characteristics include respective first        and second codes, and    -   the transmitting unit is configured to configure the first and        second power signals to have the respective first and second        codes.

In an application, the transmitting unit is configured to transmit acontrol signal, and each implant is configured to apply the treatment inresponse to the control signal.

In an application, the transmitting unit is configured to modulate thecontrol signal onto the power signal.

In an application:

-   -   the first implant is configured to receive the control signal,        and to apply the treatment after a first duration following        receiving the control signal, and    -   the second implant is configured to receive the control signal,        and to apply the treatment after a second duration following        receiving the control signal, the second duration being longer        than the first duration.

In an application, the transmitting unit is configured to configure thepower signal to be at least as long as the second duration.

In an application:

-   -   the transmitting unit is configured to transmit a plurality of        control signals, including at least first and second control        signals,    -   the first implant is configured to apply the treatment in        response to the first control signal, and    -   the second implant is configured to apply the treatment in        response to the second control signal.

In an application, the transmitting unit is configured to transmit thepower signal at least during the transmission of both the first and thesecond control signals.

In an application, the first and second implants are each configured toapply the treatment while receiving the first and second controlsignals, respectively.

In an application, the apparatus includes a plurality of implants thatinclude at least the first and second implants, and the apparatus isconfigured such that each implant is implantable at a pre-selecteddistance from another one of the implants.

In an application, the apparatus further includes a support to which atleast two of the implants are couplable, at the pre-selected distancefrom one another.

In an application, the support includes a stent, configured to beimplanted in a tubular structure of the subject.

In an application, the support includes a cuff, configured to bedisposed around a tubular structure of the subject.

In an application, the support includes a delivery device, configured tofacilitate the implantation at the pre-selected distance.

In an application:

-   -   the delivery device has a distal portion and a proximal portion,    -   the delivery device includes a release member at the proximal        portion, and    -   the at least two of the implants are decouplable from the distal        portion of the delivery device, by activation of the release        member at the proximal portion.

There is further provided, in accordance with an application of thepresent invention, apparatus for applying a treatment to a tissue of asubject,

-   -   the apparatus including a medical implant,    -   the implant including a plurality of components,        -   at least one of the components including a circuitry unit,            which is injectably implantable into the subject,        -   at least one of the components including an effector            element, which is not injectably implantable into the            subject, and which is flexibly coupled to the circuitry            unit.

In an application, the implant does not include a power supply that isable to continuously power the implant for a period greater than oneminute.

In an application, the effector element includes an electrode.

In an application, the apparatus further includes a nerve cuff, thenerve cuff including the electrode.

There is further provided, in accordance with an application of thepresent invention, apparatus for treating a condition of a subject, theapparatus including an implant, the implant:

-   -   having a skin-facing side on which at least one effector element        is disposed,    -   having an opposing side on which no effector element is        disposed,    -   being configured to be implanted at an implantation site that is        deeper than a surface of skin of the subject, such that the        skin-facing side faces superficially, and    -   including a circuitry unit, configured to drive the effector        element to apply a treatment that stimulates sensory fibers of        the skin of the subject.

In an application, the implant is configured to be implantedsubcutaneously.

In an application, the implant is configured to be implantedintradermally.

In an application, the implant does not include a power supply that isable to continuously power the implant for a period greater than oneminute.

In an application, the effector element includes a vibrating element,and the circuitry unit is configured to drive the vibrating element tostimulate the sensory fibers, by driving the vibrating element tovibrate.

In an application, the implant is configured not to induce contractionof a muscle of the subject.

In an application, the effector element is disposed farther than 1 mmfrom any lateral edge of the implant.

In an application, the effector element is disposed farther than 2 mmfrom any lateral edge of the implant.

In an application, the effector element is disposed farther than 5 mmfrom any lateral edge of the implant.

In an application, the apparatus further includes a transmitting unit,configured to transmit wireless power, and the implant is configured toreceive the wireless power.

In an application, the implant is configured to apply the treatment inresponse to receiving the wireless power.

In an application, the implant is configured to apply the treatment onlywhen the implant receives the wireless power.

In an application, the implant has a height, from the skin-facing sideto the opposing side of the implant, that is smaller than both a longestlength and a width of the implant.

In an application, the implant is generally flat.

In an application, the implant is generally shaped to define a prismthat has a transverse cross-sectional shape that is generallysemicircular.

In an application, the implant is generally shaped to define a prismthat has a transverse cross-sectional shape that is generallyelliptical.

In an application, the implant is configured not to directly initiateaction potentials in a nerve of the subject.

In an application, the implant is configured not to directly initiatethe action potentials in the nerve of the subject, by being configuredto apply the treatment that stimulates sensory fibers of the skin of thesubject from an implantation site that is farther than 1 cm from thenerve of the subject.

In an application, the implant is configured not to directly initiatethe action potentials in the nerve of the subject, by being configuredto apply the treatment that stimulates sensory fibers of the skin of thesubject from an implantation site that is farther than 2 cm from thenerve of the subject.

In an application, the implant is configured not to directly initiatethe action potentials in the nerve of the subject, by being configuredto apply the treatment that stimulates sensory fibers of the skin of thesubject from an implantation site that is farther than 3 cm from thenerve of the subject.

In an application, the effector element includes an electrode, and thecircuitry unit is configured to drive the electrode to stimulate thesensory fibers, by driving a current through the electrode.

In an application, the implant is configured not to directly initiatethe actions potentials in the nerve of the subject, by the circuitryunit being configured to configure the current not to directly initiatethe action potentials in the nerve of the subject.

In an application, the implant is configured not to directly initiateaction potentials in the nerve of the subject, by being configured todirect the treatment superficially from the implant.

In an application, the implant is configured to direct the treatmentsuperficially, by the effector element being disposed on the skin-facingsuperficial side of the implant.

In an application, the implant is configured to direct the treatmentsuperficially, by the implant including an insulating member, disposedon the opposing side of the implant.

In an application, the implant is configured to induce a sensation inthe skin of the subject.

In an application, the effector element includes an electrode, and thecircuitry unit is configured to drive the electrode to stimulate thesensory fibers, by driving a current through the electrode.

In an application, the implant is configured, when implanted at theimplantation site, to drive the current superficially to the implant.

In an application, the implant further includes an accelerometer,configured to detect movement of at least the implant.

In an application, the implant is configured to be implanted in a limbof the subject, and the accelerometer is configured to detect movementof the limb of the subject.

In an application, the implant is configured to be implanted in a limbof the subject that is affected by tremor, and the accelerometer isconfigured to detect the tremor of the limb of the subject.

In an application, the circuitry unit is configured to configure thetreatment at least in part responsively to the detection of themovement.

In an application, the movement has a phase, and the circuitry unit isconfigured to configure the treatment by applying the treatment in phasewith the phase of the movement.

In an application, the circuitry unit is configured to configure thetreatment by altering an angle of phase of the treatment with respect tothe phase of the movement.

In an application, the treatment includes application of an electricalcurrent, and the circuitry unit is configured to configure the treatmentby configuring one or more parameters of the current selected from thegroup consisting of: an amplitude of the current, a frequency of thecurrent, a pulse-width of the current, and an on-off pattern of thecurrent.

There is further provided, in accordance with an application of thepresent invention, apparatus for applying a treatment to a tissue of asubject, the apparatus including a medical implant, the implantincluding:

-   -   an injectable circuitry unit;    -   at least one effector element, coupled to the circuitry unit,        and configured to be driven by the circuitry unit to apply the        treatment;    -   at least one anchor, coupled to the circuitry unit, and having a        delivery configuration, and an anchoring configuration in which,        when the implant is implanted in the tissue of the subject, the        anchor inhibits movement of the implant along a longitudinal        axis thereof.

In an application, the implant does not include a power supply that isable to continuously power the implant for a period greater than oneminute.

In an application, the apparatus further includes a delivery device,shaped to define a lumen, and:

-   -   the implant is disposable in, slidable through, and slidable out        of the lumen of the delivery device, and is deliverable to the        tissue of the subject by sliding the device out of the lumen of        the delivery device, and    -   the anchors are configured:        -   when the implant is disposed in the lumen of the delivery            device, to be constrained by the delivery device in the            delivery configuration, and        -   when the implant is slid out of the lumen of the delivery            device, to automatically move toward the anchoring            configuration.

There is further provided, in accordance with an application of thepresent invention, apparatus for applying at least one treatment to asubject, the apparatus including:

-   -   a first transmitting unit, configured to transmit a first        wireless signal;    -   a second transmitting unit, configured to transmit a second        wireless signal;    -   a first implant, configured to be implanted at a first        implantation site of the subject, and to apply the at least one        treatment to the subject in response to the first wireless        signal; and    -   a second implant, configured to be implanted at a second        implantation site of the subject, to apply the at least one        treatment to the subject in response to the second wireless        signal, and not to apply the at least one treatment to the        subject in response to the first wireless signal.

In an application, each implant does not include a power supply that isable to continuously power the implant for a period greater than oneminute.

In an application, the first transmitting unit is configured toconfigure the first wireless signal to have a first frequency, and thesecond transmitting unit is configured to configure the second wirelesssignal to have a second frequency that is different from the firstfrequency.

In an application:

-   -   the first and second wireless signals include first and second        wireless power signals,    -   the first implant is configured to receive power from the first        power signal, and    -   the second implant is configured to receive power from the        second power signal, and not to receive power from the first        power signal.

In an application, the transmitting units are configured to be coupledto the subject.

In an application, the implants are configured to be implanted such thatthe implants are disposed, at least part of the time, within 30 cm ofeach other.

In an application, the first implant is configured to be implanted in afirst leg of the subject and the second implant is configured to beimplanted in a second leg of the subject.

In an application, the first transmitting unit is configured to becoupled to the first leg of the subject, and the second transmittingunit is configured to be coupled to the second leg of the subject.

There is further provided, in accordance with an application of thepresent invention, a method for use with a medical implant forimplanting at a tissue of a subject, the method including:

-   -   percutaneously delivering at least part of at least one        temporary electrode to the tissue of the subject;    -   electrically stimulating the tissue of the subject for between 1        and 120 minutes, using the temporary electrode;    -   receiving information indicative of a desired change in a        sensation experienced by the subject between a time before a        start of the electrical stimulation and a time after a start of        the electrical stimulation; and    -   at least in part responsively to the received information,        implanting the medical implant at the tissue of the subject.

In an application, electrically stimulating includes electricallystimulating the tissue for between 10 and 30 minutes.

In an application, receiving the information indicative of the desiredchange in the sensation includes receiving information indicative of adesired change in a pain experienced by the subject.

In an application, receiving the information indicative of the desiredchange in the sensation includes receiving information indicative ofparesthesia induced by the electrical stimulation of the tissue of thesubject.

In an application, the method further includes:

-   -   receiving a first value indicative of the factor before the        electrical stimulation; and    -   receiving a second value indicative of the factor after the        electrical stimulation,    -   and receiving the information indicative of the change in the        factor includes receiving a value indicative of a difference        between the first value and the second value.

In an application, receiving the information indicative of the change inthe factor, includes receiving information indicative of a change inpain experienced by the subject.

In an application, the tissue of the subject includes a tibial nerve ofthe subject, and stimulating the tissue of the subject includesstimulating the tibial nerve of the subject.

There is further provided, in accordance with an application of thepresent invention, a method for applying a treatment to at least onetissue of a subject, the method including:

-   -   transmitting a wireless power signal;    -   receiving the power signal using a first implant and a second        implant, each of the implants being implanted at the tissue of        the subject; and    -   in response to receiving the power signal, asynchronously        applying the treatment using the first implant and using the        second implant.

In an application, transmitting includes extracorporeally transmittingthe wireless power signal.

In an application, receiving the power signal includes subcutaneouslyreceiving the power signal using the first and second implants.

In an application, receiving the power signal includes receiving thepower signal using the first and second implants, after they have beentransluminally implanted.

In an application, asynchronously applying the treatment includes:

-   -   receiving the power signal using the first implant, and applying        the treatment using the first implant after a first duration        following receiving the power signal; and    -   receiving the power signal using the second implant, and        applying the treatment using the second implant after a second        duration following receiving the power signal, the second        duration being longer than the first duration.

In an application:

-   -   transmitting the power signal includes transmitting a plurality        of wireless power signals, including at least first and second        wireless power signals, and    -   receiving the power signal includes receiving the first power        signal using the first implant, and receiving the second power        signal using the second implant.

In an application, transmitting includes transmitting the first andsecond power signals asynchronously.

In an application, applying the treatment includes:

-   -   applying the treatment using the first implant in response to        the first power signal and not in response to the second power        signal; and    -   applying the treatment using the second implant in response to        the second power signal and not in response to the first power        signal.

In an application, applying the treatment includes:

-   -   applying the treatment using the first implant while receiving        the first power signal; and    -   applying the treatment using the second implant while receiving        the second power signal.

In an application:

-   -   transmitting the first and second power signals includes        transmitting first and second power signals that have respective        first and second characteristics that differ from one another,    -   receiving power from the first power signal, using the first        implant, in response to an effect of the first characteristic on        the first implant, and    -   receiving power from the second power signal, using the second        implant, in response to an effect of the second characteristic        on the second implant.

In an application:

-   -   the first and second characteristics include respective first        and second frequencies, and    -   transmitting includes transmitting first and second power        signals that have the respective first and second frequencies.

In an application:

-   -   the first and second characteristics include respective first        and second codes, and    -   transmitting includes transmitting first and second power        signals that have the respective first and second codes.

In an application, the method further includes:

-   -   transmitting a control signal; and    -   receiving the control signal using the first and second        implants,    -   and asynchronously applying the treatment includes, in response        to the control signal, asynchronously applying the treatment        using the first implant and using the second implant.

In an application, transmitting the control signal includes modulatingthe control signal onto the power signal.

In an application, asynchronously applying the treatment includes:

-   -   receiving the control signal using the first implant, and        applying the treatment using the first implant after a first        duration following receiving the control signal; and    -   receiving the control signal using the second implant, and        applying the treatment using the second implant after a second        duration following receiving the control signal, the second        duration being longer than the first duration.

In an application, transmitting the power signal includes transmittingthe power signal for a duration that is at least as long as the secondduration.

In an application:

-   -   transmitting the control signal includes transmitting a        plurality of control signals, including at least first and        second control signals, and    -   asynchronously applying the treatment includes:        -   applying the treatment using the first implant in response            to the first control signal; and        -   applying the treatment using the second implant in response            to the second control signal.

In an application, transmitting the power signal includes transmittingthe power signal at least during the transmission of both the first andthe second control signals.

In an application, applying the treatment using the first implantincludes applying the treatment using the first implant while receivingthe first control signal, and applying the treatment using the secondimplant includes applying the treatment using the second implant whilereceiving the second control signal.

In an application, receiving the power signal includes receiving thepower signal using the first and second implants, after each of theimplants has been implanted at a pre-selected distance from the otherone of the implants.

In an application, the implants are couplable to a support at thepre-selected distance from one another, and receiving the power signalincludes receiving the power signal using the first and second implants,after the support has been implanted in a tubular structure of thesubject.

In an application, the support includes a stent, and receiving the powersignal includes receiving the power signal using the first and secondimplants, after the stent has been implanted in the tubular structure ofthe subject.

In an application, the support includes a cuff, and receiving the powersignal includes receiving the power signal using the first and secondimplants, after the cuff has been implanted in the tubular structure ofthe subject.

In an application, the support includes a delivery device, and receivingthe power signal includes receiving the power signal using the first andsecond implants, after the stent has been implanted using the deliverydevice.

In an application, receiving the power signal includes receiving thepower signal using the first and second implants, after the stent hasbeen decoupled from the delivery device.

There is further provided, in accordance with an application of thepresent invention, a method for treating a condition of a subject, themethod including:

-   -   driving a subcutaneously-implanted effector element to apply a        treatment that stimulates sensory fibers of skin of the subject;        and    -   using an inhibiting element, inhibiting direct stimulation of a        nerve of the subject that is closest to the effector element,        during the application of the treatment by the effector element.

In an application, inhibiting the direct stimulation of the nerveincludes preventing direct initiation of action potentials in the nerve.

In an application, inhibiting the direct stimulation of the nerveincludes preventing direct initiation of action potentials in an ulnarnerve of the subject.

In an application, inhibiting the direct stimulation of the nerveincludes preventing direct initiation of action potentials in a mediannerve of the subject.

In an application, inhibiting the direct stimulation of the nerveincludes preventing direct initiation of action potentials in a nerve ofthe subject that is disposed deeper than the inhibiting element.

In an application, driving the effector element to apply the treatmentincludes driving the effector element to vibrate.

In an application, inhibiting further includes inhibiting directinduction of contraction of a muscle of the subject.

In an application, driving the effector element includes driving theeffector element using an implanted circuitry unit.

In an application, driving the effector element includes wirelesslydriving the effector element.

In an application, inhibiting the direct stimulation of the nerveincludes directing the treatment away from the nerve.

In an application, directing the treatment includes directing thetreatment superficially.

In an application, driving the effector element includes driving theeffector element after an implant that includes the effector element hasbeen subcutaneously implanted in the subject.

In an application, the effector element is disposed only on askin-facing side of the implant, and inhibiting the direct stimulationof the nerve includes driving the effector element that is disposed onthe skin-facing side of the implant.

In an application, inhibiting the direct stimulation of the nerveincludes insulating the nerve from the treatment using the inhibitingelement.

In an application, insulating includes electrically insulating the nervefrom the treatment.

In an application, insulating includes mechanically insulating the nervefrom the treatment.

In an application, driving the effector element includes driving theeffector element after an implant that (1) has a height from a lowerportion to an upper portion of the implant that is smaller than both alongest length and a width of the implant, and (2) includes the effectorelement, has been subcutaneously implanted in the subject.

In an application, driving the effector element includes driving theeffector element after an implant that (1) is generally shaped to definea prism that has a transverse cross-sectional shape that is generallysemicircular, and (2) includes the effector element, has beensubcutaneously implanted in the subject.

In an application, driving the effector element includes driving theeffector element after an implant that (1) is generally shaped to definea prism that has a transverse cross-sectional shape that is generallyelliptical, and (2) includes the effector element, has beensubcutaneously implanted in the subject.

In an application, driving the effector element includes driving theeffector element after an implant that (1) is generally flat, and (2),includes the effector element, has been subcutaneously implanted in thesubject.

In an application, inhibiting the direct stimulation of the nerveincludes inhibiting the direct stimulation of the nerve by driving theeffector element after an implant that includes the effector element hasbeen implanted at an implantation site that is farther than 1 cm fromthe nerve of the subject.

In an application, inhibiting the direct stimulation of the nerveincludes inhibiting the direct stimulation of the nerve by driving theeffector element after an implant that includes the effector element hasbeen implanted at an implantation site that is farther than 2 cm fromthe nerve of the subject.

In an application, inhibiting the direct stimulation of the nerveincludes inhibiting the direct stimulation of the nerve by driving theeffector element after an implant that includes the effector element hasbeen implanted at an implantation site that is farther than 3 cm fromthe nerve of the subject.

In an application, the effector element includes an electrode, anddriving the effector element to apply the treatment includes driving acurrent through the electrode.

In an application, inhibiting the direct stimulation of the nerveincludes configuring the current not to directly stimulate the nerve ofthe subject.

In an application, inhibiting the direct stimulation includes directingthe current superficially.

In an application, the method further includes detecting movement of alimb of the subject in which the effector element has been implanted,and driving the effector element includes driving the effector elementat least in part responsively to the detected movement.

In an application, detecting the movement includes detecting movement ofthe limb of the subject by detecting movement of an accelerometer thatis coupled to the effector element.

In an application, detecting the movement of the limb of the subjectincludes detecting tremor of the limb of the subject.

In an application, driving the effector element at least in partresponsively to the detected movement includes configuring the treatmentat least in part responsively to the detected movement.

In an application, the movement of the limb has a frequency, andconfiguring the treatment includes configuring the treatment to have thefrequency of the movement of the limb.

In an application, configuring the treatment includes configuring thetreatment to be in phase with a phase of the movement of the limb.

In an application, configuring the treatment includes configuring thetreatment to be out of phase with a phase of the movement of the limb.

There is further provided, in accordance with an application of thepresent invention, an implant, including:

-   -   a circuitry unit, configured to receive power wirelessly;    -   a lead, having a proximal end and a distal end, the proximal end        configured to be coupled to the circuitry unit; and    -   an array of microelectrodes, configured to be coupled to the        circuitry unit by the lead, and configured to be coupled to a        carotid sinus of a patient.

In an application, the microelectrodes are configured to contact one ormore baroreceptors in the carotid sinus.

In an application, the circuitry unit is configured to drive themicroelectrodes to deliver a current between 1 and 100 microamps.

In an application, the circuitry unit is configured to separately driveeach microelectrode to apply a respective voltage.

There is further provided, in accordance with an application of thepresent invention, an implant, including:

-   -   a circuitry unit, configured to receive power wirelessly; and    -   an array of microelectrodes, disposed on an outer surface of the        circuitry unit.

The present invention will be more fully understood from the followingdetailed description of applications thereof, taken together with thedrawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration of a system for wirelessneurostimulation, in accordance with some applications of the presentinvention;

FIG. 2 is a schematic illustration of another system for wirelessneurostimulation, in accordance with some applications of the presentinvention;

FIG. 3 is a schematic illustration of another system for wirelessneurostimulation, in accordance with some applications of the presentinvention;

FIG. 4 is a schematic illustration of another system for wirelessneurostimulation, in accordance with some applications of the presentinvention;

FIG. 5 is a schematic illustration of another system for wirelessneurostimulation, in accordance with some applications of the presentinvention;

FIG. 6 is a schematic illustration of another system for wirelessneurostimulation, in accordance with some applications of the presentinvention;

FIG. 7 is a schematic illustration of another system for wirelessneurostimulation, in accordance with some applications of the presentinvention;

FIGS. 8A-C are schematic illustrations of another system for wirelessneurostimulation, in accordance with some applications of the presentinvention;

FIGS. 9A-B are schematic illustrations of another system for wirelessneurostimulation, in accordance with respective applications of thepresent invention;

FIGS. 10A-C are schematic illustrations of another system for wirelessneurostimulation, in accordance with some applications of the presentinvention;

FIG. 11 is a schematic illustration of another system for wirelessneurostimulation, in accordance with some applications of the presentinvention;

FIG. 12 is a schematic illustration of another system for wirelessneurostimulation, in accordance with some applications of the presentinvention;

FIGS. 13A-B are schematic illustrations of implantation sites forimplanting implants, in accordance with some applications of theinvention;

FIGS. 14A-C are schematic illustrations of a system for asynchronousapplication of treatment using a plurality of implants, in accordancewith some applications of the invention;

FIG. 15 is a schematic illustration of a system for asynchronousapplication of treatment using a plurality of implants, in accordancewith some applications of the invention;

FIG. 16 is a schematic illustration of a system for asynchronousapplication of treatment using a plurality of implants, in accordancewith some applications of the invention; and

FIGS. 17A-E are schematic illustrations of an antenna for use withsystems for wireless neurostimulation, in accordance with respectiveapplications of the invention.

DETAILED DESCRIPTION OF APPLICATIONS

Reference is made to FIG. 1, which is a schematic illustration ofmedical implant 20, comprising a circuitry unit 22, and one or moreeffector elements, such as electrodes 28 (e.g., electrodes 28 a and 28b), in accordance with some applications of the invention. At least oneelectrode (e.g., electrode 28 b) is coupled to circuitry unit 22 via alead 24. Typically, at least another electrode (e.g., electrode 28 a) isdisposed on a surface of the circuitry unit. Circuitry unit 22 isconfigured to drive a current through electrodes 28. For someapplications of the invention, implant 20 further comprises a nerve cuff26, e.g., as is known in the art, and the nerve cuff comprises theelectrode that is coupled to the circuitry unit via the lead. Forexample, electrode 28 b may be disposed on an inner surface of the nervecuff.

For some applications of the invention, circuitry unit 22 comprises oris coupled to an antenna 30. Antenna 30 is illustrated as a coiledantenna purely as an example, but may take other forms, such as, but notlimited to, those described with reference to FIGS. 17A-E. Antenna 30 isconfigured to receive data and/or power wirelessly from an externaldevice, such as an extracorporeal device (e.g., a mattress-basedtransmitting unit, or a transmitting unit coupled to a belt, hat,eyeglasses, or clothing item of the patient) or another implant. Forsome applications, antenna 30 receives power wirelessly from animplanted transmitting unit coupled to a power supply (e.g., a battery).Alternatively or additionally, the circuitry unit receives power from apower supply (e.g., a battery), which may be in a common housing withthe circuitry unit.

Circuitry unit 22 is typically small and tubular (e.g., 1-6 mm indiameter, and 5-50 mm in length), although the scope of the presentinvention includes other shapes for the circuitry unit (e.g., prismaticshapes, as described hereinbelow). For some applications, at least thecircuitry unit itself is “injected” into a desired implantation site,using techniques known for implanting a BION™. For some applications,the entire implant is configured to be injectable. Similarly, except fordifferences noted herein, the circuitry unit typically comprisesstimulation and/or sensing circuitry as is known for a BION™ or othertissue stimulation devices.

Reference is now made to FIG. 2, which is a schematic illustration ofmedical implant 40, comprising generally the same components as implant20 shown in FIG. 1, except that both electrodes 28 (e.g., electrodes 28a and 28 b) are coupled to circuitry unit 22 via lead 24, in accordancewith some applications of the invention. For some applications, implant40 comprises nerve cuff 26, and electrodes 28 are disposed on the nervecuff, as described hereinabove.

Reference is now made to FIG. 3, which is a schematic illustration ofmedical implant 50, comprising generally the same components as implant40 shown in FIG. 2, except that electrodes 28 (e.g., electrodes 28 a and28 b) are coupled to circuitry unit 22 via respective leads 24 (e.g.,leads 24 a and 24 b), in accordance with some applications of theinvention. For some applications, implant 50 comprises two or more nervecuffs 26 (e.g., nerve cuffs 26 a and 26 b), and the electrodes aredisposed on respective nerve cuffs.

Reference is now made to FIG. 4, which is a schematic illustration ofmedical implant 60, comprising generally the same components as implant20 shown in FIG. 1, except that the implant comprises a third electrode28 c, in accordance with some applications of the invention. For someapplications, electrodes 28 a, 28 b and 28 c are disposed on nerve cuff26. For some applications of the invention, third electrode 28 c isconfigured to facilitate unidirectional action potential propagation inthe nerve. It is noted that, in accordance with some applications of thepresent invention, bidirectional stimulation is also possible usingmedical implant 60.

Reference is now made to FIG. 5, which is a schematic illustration ofmedical implant 70, comprising generally the same components as implant20 shown in FIG. 1, except that both electrodes 28 are disposed on theouter surface of circuitry unit 22, and, rather than the circuitry unitcomprising antenna 30, the antenna is disposed outside of the circuitryunit, and is coupled to the circuitry unit via a lead 72, in accordancewith some applications of the invention. For some applications of theinvention, antenna 30 may receive power and/or data, and/or may sendsensing or diagnostic data acquired by circuitry unit 22 (e.g., dataindicative of a state of the nerve of the patient). It is noted thatalthough the circuitry unit of implant 70 is shown as having twoelectrodes on its outer surface, implant 70 may alternatively beconfigured as shown in other figures (e.g., FIG. 1-4, 6-10C, or 11-12).For some such applications, the circuitry unit may in turn be coupled toone or more nerve cuffs or other implant for supporting electrodes in asuitable position for stimulating tissue.

Reference is now made to FIG. 6, which is a schematic illustration ofmedical implant 80, comprising generally the same components as implant20 shown in FIG. 1, except that circuitry unit 22 is coupled via lead 24to a microelectrode array 82, comprising a plurality of microelectrodes84, in accordance with an application of the present invention, inaccordance with some applications of the invention. It is noted that theplurality of microelectrodes 84 are not drawn to scale. For someapplications, microelectrode array 82 is flexible, in order to moreclosely conform to the shape of a tissue into which the microelectrodespenetrate. For example, array 82 may be placed generally flat against alarge structure (e.g., the heart or a portion of the gastrointestinaltract) or a large-diameter structure (e.g., the spinal cord), or array82 may be at least partially (e.g., completely) wrapped around astructure, such as a nerve or a blood vessel.

According to some applications of the present invention, microelectrodearray 82 may be coupled to a carotid sinus of the patient, and morespecifically to baroreceptors in the carotid sinus. According to oneapplication of the present invention, each microelectrode 84 isindividually controllable by circuitry unit 22, thereby facilitating acalibration period in which the effect of current from eachmicroelectrode on baroreceptor activity and/or blood pressure may beassessed, and in which a stimulation protocol for each microelectrodemay be created. For example, each microelectrode may be individuallycoupled to circuitry unit 22, or may be coupled to the circuitry unitvia a multiplexer.

For some applications of the invention, the techniques described for usewith implant 80 and/or microelectrode array 82 may be combined withother implants described herein. For example, each microelectrode of themicroelectrode array of implant 90, described with reference to FIG. 7,may be individually controllable, as described for the microelectrodesof implant 80, mutatis mutandis. Alternatively or additionally, one ormore other implants described herein may be configured and/or implantedto stimulate baroreceptors of a subject, such as baroreceptors of thecarotid artery of the subject.

According to some applications of the present invention, microelectrodes84 each deliver a current that is less than 1000 microamps, e.g., 10-100microamps, or 1-10 microamps.

Reference is now made to FIG. 7, which is a schematic illustrationshowing a cross-section of medical implant 90, comprising generally thesame components as implant 80 shown in FIG. 6, except that at least onemicroelectrode array 82, comprising microelectrodes 84, is disposed onthe outer surface of circuitry unit 22, in accordance with someapplications of the invention. It is again noted that microelectrodes 84are not drawn to scale.

Reference is now made to FIGS. 8A-C, which are schematic illustrationsof medical implant 100, comprising circuitry unit 22, electrodes 28, anda flexible tubular element 52, in accordance with respectiveapplications of the invention. For some applications of the invention,implant 100 is analogous to medical implant described hereinabove, suchas implant 20. Tubular element 52 typically comprises flexible silicone.Circuitry unit 22 is typically disposed inside tubular element 52, andat least part of each electrode 28 is exposed at an outer surface ofelement 52. For some applications, electrodes 28 are disposed on theoutside of element 52. Leads 24 electrically couple respectiveelectrodes 28 to circuitry unit 22, and are typically disposed withinelement 52. Typically, implant 100 is injectable (e.g., percutaneouslyinjectable), as described hereinabove.

For some applications of the invention, and as shown in FIG. 8A,circuitry unit 22 comprises antenna 30 (e.g., as described withreference to FIG. 1). For some applications of the invention, and asshown in FIG. 8B, antenna is disposed outside of the circuitry unit, andis coupled to the circuitry unit via lead 72 (e.g., as described withreference to FIG. 5). FIGS. 8A-B show circuitry unit 22 being disposedgenerally midway along the length of tubular element 52. However, otherconfigurations may be used. For example, and as shown in FIG. 8C,circuitry unit 22 may be disposed at one end of element 52, and/or anelectrode 28 may be disposed on the outer surface of the circuitry unit.

For applications of the invention in which circuitry unit 22 is disposedwithin flexible tubular casing 52 (e.g., as described with reference toFIGS. 8A-C, and 10C), the circuitry unit typically comprises ahermetically-sealed casing, such as a ceramic or glass casing.

Reference is again made to FIGS. 1-6 and 8A-C. Circuitry unit 22comprises circuitry, such as an application-specific integrated circuit(ASIC), and is typically (e.g., necessarily) rigid. Typically, eachimplant described with reference to FIGS. 1-6 and 8A-C (e.g., implants20, 40, 50, 60, 70, 80, and/or 100) is configured such that at least twoof the components of the implant are flexibly coupled to each other. Forexample, electrodes 28 and/or antenna 30 may be flexibly coupled tocircuitry unit 22. Leads 24 and 72, and tubular element 52 are typicallyflexible, and typically provide such flexible coupling. For someapplications, at least one component that would otherwise be disposed inor on an injectable stimulatory implant, such as a BION™ (e.g., anantenna and/or an electrode), is disposed outside of circuitry unit 22.For some such applications, this configuration thereby facilitates theminiaturization of circuitry unit 22, e.g., such that circuitry unit 22is smaller than a BION™. For some applications, at least one componentthat would otherwise be rigidly coupled to a circuitry unit of aninjectable stimulatory implant, such as a BION™, is, in the presentinvention, flexibly coupled to circuitry unit 22. It is hypothesizedthat this flexible coupling and/or this miniaturization of circuitryunit 22, facilitates maintenance of contact between the electrodes andthe tissue into which the current is being driven and/or increasesversatility of the implant, e.g., by facilitating placement of theimplant in positions in which a fully-rigid implant is not placeable.

Reference is made to FIGS. 9A-B, which are schematic illustrations ofmedical implant 110, and steps in the implantation thereof, inaccordance with respective applications of the invention. Implant 110comprises circuitry unit 22, one or more electrodes 28 (e.g., electrodes28 a and 28 b), and one or more anchors 112. For some applications ofthe invention, implant 110 is analogous to medical implant describedhereinabove, such as implant 20. FIG. 9A shows implant 110 embodied asimplant 110 a, comprising anchors 112, embodied as anchors 112 a.

FIG. 9B shows implant 110 embodied as implant 110 b, comprising anchors112, embodied as anchors 112 b.

Anchors 112 are configured to inhibit movement of implant 110, followingdelivery of the implant to the desired implantation site. Implant 110 istypically “injected” into the desired implantation site, e.g., usingtechniques known for implanting a BION™. Typically, anchors 112 have (1)a delivery configuration, in which the anchors are configured to fitwithin, and be slidable through, a lumen of a delivery device 114, suchas a hollow needle, and (2) an anchoring configuration in which theanchors protrude laterally and/or radially from the body of implant 110(e.g., from circuitry unit 22), and into tissue at the implantationsite. As shown in step (1) of FIG. 9A, anchors 112 a, in the deliveryconfiguration thereof, are disposed against the body of implant 110(e.g., against circuitry unit 22).

As shown in step (1) of FIG. 9B, anchors 112 b, in the deliveryconfiguration thereof, are typically generally straight, and aredisposed proximally and/or distally from the body of implant 110 (e.g.,from circuitry unit 22). That is, in the delivery configuration, anchors112 generally do not inhibit movement of implant 110 along alongitudinal axis thereof, and in the anchoring configuration, theanchors generally do inhibit such movement. Typically, anchors 112 areconfigured to be biased toward assuming the anchoring configuration, andare constrained in the delivery configuration by delivery device 114,e.g., as shown in FIG. 9A. As implant 110 is exposed from deliverydevice 114, anchors 112 automatically move toward the anchoringconfiguration, e.g., as shown in steps (2) and (3) of FIGS. 9A and 9B.Typically, anchors 112 are thus configured by comprising a shape-memorymaterial that is shape-set in the anchoring configuration. Non-limitingexamples of materials that anchors 112 may comprise includenickel-titanium (Nitinol), stainless steel, nickel cobalt, cobaltchrome, titanium, tantalum, and palladium.

As shown in steps (2) and (3) of FIG. 9A and FIG. 9B, movement ofanchors 112 toward the anchoring configuration thereof comprisesrotation (e.g., deflection) of the anchors around a coupling point ofthe anchors to circuitry unit 22, and/or bending of the anchors, suchthat at least a portion of each anchor protrudes laterally and/orradially from circuitry unit 22.

Although FIGS. 9A-B show implant 110 (e.g., implants 110 a and 110 b)comprising 2 anchors 112 at each end of the implant, the scope of theinvention includes other numbers and/or arrangements of anchors. Forexample, implant 110 may comprise 3 or more anchors 112 at each end ofthe implant, or may comprise anchors only at one end of the implant.

It is to be noted that anchors 112 (e.g., anchors 112 a and 112 b) areshown and described with reference to FIGS. 9A-B as illustrativeexamples, and the scope of the invention includes other embodiments ofanchors 112.

It is to be noted that the configuration of the circuitry unit andelectrodes of implant 110 shown in FIGS. 9A-B is for illustration, andthe circuitry unit and electrodes of implant 110 may alternatively beconfigured as shown in other figures (e.g., FIG. 1-8C, 10A-C, or 11-12).Similarly, anchors 112 may be used in combination with other medicalimplant described herein (e.g., with the circuitry units, electrodes,antennae, and/or tubular elements thereof).

Reference is made to FIGS. 10A-C, which are schematic illustrations ofmedical implant 120, comprising circuitry unit 22, electrodes 28, and anaccelerometer 122, in accordance with respective applications of theinvention. For some applications of the invention, implant 120 isanalogous to medical implant described hereinabove, such as implant 20.Accelerometer 122 is configured to sense movement of the site at whichimplant 120 is implanted, and to responsively provide a signal tocircuitry unit 22. For example, when implant 120 is used to treat amovement disorder, accelerometer 122 may be used to sense incidents of,and/or improvement in, the disorder, e.g., as described hereinbelow withreference to FIGS. 13A-B. Similarly, accelerometer 122 may be used tosense when the subject is at a specific level of activity (e.g., atrest) and/or in a specific position (e.g., lying down or standing up),and circuitry unit 22 is configured to drive the current in response tothe sensed activity level and/or position.

FIG. 10A shows an application of the invention in which accelerometer122 is disposed within circuitry unit 22. FIG. 10B shows an applicationof the invention in which accelerometer 122 is disposed outside ofcircuitry unit 22, and is coupled to the circuitry unit via a lead 124.FIG. 10C shows an application of the invention in which accelerometer122 is disposed outside of circuitry unit 22, is coupled to thecircuitry unit via lead 124, and is disposed within tubular element 52.Although FIGS. 10A-C show specific examples of applications of theinvention in which the medical implant comprises accelerometer 122, theuse of accelerometer 122 may be combined with other medical implantdescribed herein (e.g., may be coupled to other circuitry unitsdescribed herein).

For some applications of the invention, an extracorporeal device, e.g.,a worn extracorporeal device, such as a wristwatch-based device mayalternatively or additionally comprise an accelerometer, and transmitwireless power in response to a detected movement, activity level,and/or position.

Reference is made to FIGS. 11 and 12, which are schematic illustrationsof medical implant 130 and 140, respectively, comprising circuitry unit22, and electrodes 28. Implants 130 and 140 are typically configured tobe implanted intradermally or subcutaneously. That is, implants 130 and140 are typically configured to be placed deeper than a surface of theskin of the subject (e.g., deeper than the epidermis). Implants 130 and140 are further typically configured to be implanted by “injecting”(e.g., as described hereinabove for other implants, mutatis mutandis).Typically, implant 130 and 140 are shaped to define respective prismaticshapes, having a skin-facing side, and an opposing side. Implant 130 istypically shaped to define a prism that has a transverse cross-sectionthat has a generally arced upper portion 132 that defines theskin-facing side of the implant, and a generally flat lower portion 134that defines the opposing side of the implant. For example, thetransverse cross-section of implant 130 may be generally semicircular.Implant 140 has a transverse cross-section that is generally elliptical,having a generally arced upper portion 142 that defines the skin-facingside of the implant, and a generally arced lower portion 144 thatdefines the opposing side of the implant. Implants 130 and 140 aretypically shaped such that a height d1 and d4, respectively, from theskin-facing side to the opposing side, is smaller than both (1) alongest length d2 and d5, respectively, and (2) a width d3 and d6,respectively, of the implant. That is, compared to a generallycylindrical implant, implant 130 and 140 have generally flattenedconfigurations (i.e., a “low profile”).

Typically, dimension d1 is greater than 0.5 mm and/or less than 3 mm(e.g., about 1.5 mm). Typically dimension d4 is greater than 0.5 mmand/or less than 3 mm (e.g., between 1.5 and 2 mm). Typically,dimensions d2 and d5 are greater than 5 mm and/or less than 30 mm (e.g.,between 10 and 30 mm, such as between 10 and 20 mm). Typically,dimensions d3 and d6 are greater than 1 mm and/or less than 5 mm (e.g.,between 1.5 and 3 mm).

The shapes of implant 130 and 140 are given as non-limiting examples offlattened configurations; other shapes may also be used. For example,implant 130 and/or 140 may be generally flat (e.g., sheet-like), havingelectrodes 28 disposed on one side. When the implant is flat, theimplant typically comprises a resilient material, and is configured toremain generally flat or slightly curved (e.g., not to curl up).Furthermore, other medical implant and/or circuitry units describedherein may also be configured to have a flattened configuration forintradermal and/or subcutaneous implantation.

Typically, electrodes 28 of implant 130 and 140 are disposed generallyon one side of the implant. For example, electrodes 28 of implant 130are typically disposed only on upper portion 132, and electrodes 28 ofimplant 140 are typically disposed only on upper portion 142. Thereby,implants 130 and 140 typically have a conducting side (i.e., the side onwhich the electrodes are disposed). This configuration is hypothesizedto direct the current that is driven through electrodes 28 by circuitryunit 22, to tissue at the conducting side of the implant (e.g., totissue adjacent to the upper portion of the implant). That is, implants130 and 140 are typically directional. Typically, the skin-facing sideof the implant defines the conducting side of the implant.

For some applications of the invention, and as shown for implant 130,the implant may comprise an inhibiting element, such as an insulatingmember 136, (e.g., an insulating layer), configured to inhibitelectrical conduction therethrough. Typically, insulating member 136 isdisposed on, such as coupled to, the lower portion and/or the opposingside of the implant, so as to inhibit electrical conduction fromelectrodes 28 into tissue adjacent to the lower portion of the implant,i.e., into tissue at the opposing side of the implant. Thereby,insulating member 136 contributes toward the one-sided configuration ofthe implant. Although insulating member 136 is shown as a component ofimplant 130, the insulating member may be used to facilitate theone-sidedness of medical implant 140. Element 136 may also be used incombination with other medical implant described herein. For example,one or more elements 136 may be (1) disposed around at least part ofnerve cuff 26, so as to inhibit conduction of current away from a nervearound which the cuff is disposed, or (2) disposed around at least partof a circuitry unit and/or tubular element, so as to provideone-sidedness thereto. Insulating member 136 may comprise any suitablematerial known in the art, such as insulating silicone.

For some applications of the invention in which the implant comprises aninsulating member, electrodes 28 laterally circumscribe the implant, andpart of the electrodes is covered by the insulating member. That is, forsome applications of the invention, electrodes 28 are not disposedgenerally on one side of the implant. For example, electrodes 28 ofimplant 130 may be disposed circumferentially around circuitry unit 22,and part of the electrodes is sandwiched between the circuitry unit andinsulating member 136. For some such applications, this configurationfacilitates manufacturing of the implant, e.g., by facilitating theapplication of the electrodes to the surface of the circuitry unit.

Implants 130 and 140 are thereby typically directional, having aconducting skin-facing side and, for some applications, an insulatingmember at the lower portion of the implant, which provides an insulatingopposing side of the implant. Typically, electrodes 28 of implants 130and 140 are disposed at least 1 mm (e.g., greater than 2 mm, such asgreater than 5 mm) from the lateral edges of the implant. That is, theimplants typically define respective lateral zones 131 and 141, on theskin-facing side of the implants, the lateral zones having a width ofdistance d7, in which electrodes 28 are not disposed, distance d7 beinggreater than 1 mm (e.g., greater than 2 mm, such as greater than 5 mm).For example, the lateral zone may include the insulating member (asshown in FIG. 11 for lateral zone 131 of implant 130) and/or a portionof the upper portion of the circuitry unit on which electrodes are notdisposed (e.g., as shown in FIG. 12 for lateral zone 141 of implant140). It is hypothesized that providing the lateral zone in whichelectrodes 28 are not disposed, facilitates the one-sidedness of theimplant, by inhibiting electrical conduction from electrodes 28 intotissue adjacent to the lower portion of the implant, i.e., into tissueat the opposing side of the implant.

For some applications of the invention, implants 130 and 140 definelateral zones 131 and 141 on the opposing side of the implant, and areconfigured to be implanted such that the electrodes of the implant faceaway from the skin. Thereby, for such applications, implants 130 and 140are configured to inhibit electrical conduction from the electrodes intothe skin that is superficial to the implant, e.g., so as to stimulateunderlying muscle and or nerves. It is hypothesized that, for suchapplications, current applied from electrodes 28 advantageously inducesless pain in the subject than does current from external skin-mountedelectrodes (e.g., Transcutaneous Electrical Nerve Stimulationelectrodes), e.g., due to reduced stimulation of sensory nerve fibers.

Typically, implants 130 and 140 further comprise accelerometer 122,described hereinabove with reference to FIGS. 10A-C. Alternatively,implants 130 and 140 may be used in combination with a an extracorporealdevice that comprises an accelerometer.

Reference is again made to FIGS. 1-12. Typically, at least the circuitryunits of the respective implants described hereinabove are configured tobe “injectable” (e.g., percutaneously deliverable via a hollow needle,and/or using techniques known for implanting a BION™). For someapplications, the entire implant is configured to be injectable.

For some applications, the implants described with reference to FIGS.1-12 are wirelessly powered by a transmitting device, e.g., viaradio-frequency (RF) or electromagnetic induction, such as describedhereinbelow with reference to FIGS. 14A-C, mutatis mutandis. For suchapplications, the implants typically do not comprise a power supply suchas a battery. For clarity, throughout this patent application, includingthe claims, a “power supply” is defined as an element that is configuredto continuously power the implant for a period of greater than oneminute. For some applications, the implants described with reference toFIGS. 1-12 comprise a temporary power storage element (e.g., tofacilitate a delay between receiving wireless power and applying atreatment). For clarity, throughout this patent application, includingthe claims, a “temporary power storage element” is defined as an elementthat is configured to continuously power the implant for a period of upto one minute. For some applications of the invention, the implants arepassive implants, and operate only while wireless power is received(e.g., the implants do not comprise a power supply or a temporary powerstorage element, and consume power as it is received). For some suchapplications, the transmitting device is worn by the subject, and/or isdisposed in, on, or under, an item of furniture or clothing of thesubject, such as a bed or a hat of the subject.

Alternatively, the implants described with reference to FIGS. 1-12 maycomprise a power supply (i.e., a power supply that is configured tocontinuously power the implant for a period of greater than one minute).For example, the implants may comprise a battery that is configured tocontinuously power the implant for a period of up to three days, and tobe wirelessly charged once per day (e.g., at night). Alternatively, theimplants may comprise a battery that is configured to power the implantfor more than three days (e.g., for more than a month, such as for morethan a year).

Reference is made to FIGS. 13A-B, which are schematic illustrations ofmedical implant 130, having been implanted at respective implantationsites 150 (e.g., implantation sites 150 a and 150 b) in an arm 160 of asubject, so as to treat tremor of at least the arm of the subject, inaccordance with some applications of the invention. In FIGS. 13A-B,medical implant 130 is shown as an example of such an implanted medicalimplant, but it is to be noted that the scope of the invention includesthe implantation, at the implantation sites, of other medical implants,such as those described herein, mutatis mutandis. Similarly, thetechniques described herein may also be used to treat tremor at anothersite in the body of the subject, such as in another limb of the subject,such as in a leg of the subject.

Implantation sites 150 (e.g., implantation site 150 a and implantationsite 150 b) are intradermal or subcutaneous. Typically, implant 130 isimplanted within subcutaneous tissue of a subject, and is typicallydelivered by injection (e.g., using techniques known for implanting aBION™, and/or as described with reference to FIGS. 9A-B, mutatismutandis). Subcutaneously- and intradermally-implanted implantstypically distend overlying skin and/or compress underlying tissue, dueto the volume and/or shape of the implant. As described hereinabove,implant 130 is shaped to have a low profile, compared to a similarcylindrical implant. Thereby, when implanted subcutaneously, implant 130distends overlying skin 152 and/or compresses underlying tissue, such asmuscle 154, less than does an implant with a greater profile (e.g., acylindrical implant). Typically, implant 130 is implanted such thatupper portion 132 faces the skin, and lower portion 134 faces theunderlying tissue, thereby positioning electrodes 28 toward the skinand, if the implant includes insulating member 136, positioning theinsulating member toward the underlying tissue. That is, when implantedsubcutaneously, the conducting side of the implant is typically askin-facing side of the implant. Implanting implant 130 in thisconfiguration thereby configures the implant to direct current towardthe skin and/or away from the underlying tissue.

Circuitry unit 22 is typically configured to drive a current throughelectrodes 28, and to configure the current to stimulate sensory fibersin the skin of the subject. Typically, the subject thereby feels thecurrent being delivered (i.e., the implant induces a sensation in theskin of the subject). For some applications, the current may induce atleast temporary discomfort or even pain in the subject, and, for someapplications, this is desirable for successful treatment. For someapplications, the current may be configured to have an amplitude that isgreat as possible without causing pain. For some applications, thecurrent and/or sensations induced by the current may be similar to thoseof TENS apparatus, as is known in the art. Typically, circuitry unit 22configures the current to a frequency of greater than 1 and/or less than150 Hz, but other frequencies may also be used.

It is hypothesized that stimulation of sensory fibers in the skin of thelimb of the subject (e.g., as described in the above paragraph) reducesthe intensity and/or frequency of tremor in at least that limb.Typically, the stimulation of the sensory fibers in the skin isperformed predominantly without directly stimulating underlying tissuesuch as underlying muscles and/or nerves (i.e., muscles and/or nervesthat are disposed deeper than the implant). That is, action potentialsare predominantly initiated in sensory fibers in the skin, i.e.,upstream of nerves. (In this application, the term “nerve” is intendedto be distinct from the term “sensory fiber”.) For example, the implantis typically configured so as to predominantly not (1) directly initiateaction potentials in nerves, such as ulnar nerve 156, (2) stimulatesensory fibers in underlying muscle, and/or (3) induce contraction ofunderlying muscle (e.g., spasm).

For some applications of the invention, the implant is configured toperform this selective stimulation of sensory fibers by the implantbeing directional, e.g., as described with reference to FIGS. 11-12. Forsuch applications, the implant is typically implanted such that theconducting side of the implant (e.g., the side on which electrodes aredisposed) faces superficially, thereby directing the currentsuperficially (e.g., toward the skin). Similarly, implants comprising aninsulating member are typically implanted such that the insulatingmember is disposed deeper into the subject than the electrodes. That is,for such applications, the electrodes are typically disposed on asuperficial side (e.g., a skin-facing side) of the implant, and/or theinsulating member is typically disposed on a deep side of the implant.Thereby, insulating member 136 and/or lateral zones 131 and 141 act asinhibiting elements that inhibit direct stimulation of one or morenerves disposed deeper than the implanted implant.

For some applications of the invention, the implant is configured toperform the selective stimulation of sensory fibers in the skin, bycircuitry unit 22 being configured to configure the current that itdrives via electrodes 28, to selectively stimulate the sensory fibers inthe skin. For example, circuitry unit 22 may configure the current tohave an amplitude that is sufficient to stimulate the sensory fibers inthe skin but insufficient to initiate action potentials in sensoryfibers in muscle and/or nerves, and/or to induce contraction of muscle.Alternatively or additionally, circuitry unit 22 may configure thecurrent to have another characteristic, such as a frequency, a pulsewidth, and/or an on-off pattern (i.e., durations for which the wirelesspower is transmitted and not transmitted) that facilitates suchselective stimulation of sensory fibers in the skin.

For some applications, the electrodes of the implant are disposed closeto each other (e.g., less than 10 mm from each other, such as less than2 mm from each other), so as to inhibiting the current that flowsbetween the electrodes, from flowing far from the implant, and therebyinhibiting the current that flows between the electrodes from reachingthe nerves disposed deeper than the implanted implant.

For some applications of the invention, the implant is configured toperform the selective stimulation of sensory fibers in the skin by beingimplanted sufficiently close to the sensory fibers in the skin, andsufficiently far from the underlying muscle and/or nerves. For example,and as shown in FIG. 13B, the implant may be subcutaneously implanted atimplantation site 150 b, on the lateral side (i.e., the “back”) of theforearm, which is generally farther from ulnar nerve 156 and mediannerve 157, than are sites on the medial side (i.e., the “inside”) of theforearm. For example, implantation site 150 b may be farther than 1 cm(e.g., farther than 2 cm, such as farther than 3 cm) from the ulnarnerve and/or the median nerve.

For some applications, and as shown in FIG. 13A, the implant may beotherwise sufficiently configured to perform the selective stimulationof sensory fibers (e.g., as described hereinabove), such that it ispossible to implant the implant at an implantation site, such asimplantation site 150 a, that is closer to nerves, such as nerves 156and 157, predominantly without stimulating the nerves. For someapplications of the invention, it may be even be desirable to implantthe implant at such a site, e.g., so as to facilitate stimulation ofspecific sensory fibers that conduct impulses toward one or morespecific nerves.

As described hereinabove, implant 130 typically comprises accelerometer122, which is configured to sense movement of the implantation site, andto responsively provide a signal to circuitry unit 22. Accelerometer 122is typically configured to sense tremor of the limb, and circuitry unit22 is typically configured to drive the current via electrodes 28 atleast in part responsively to the sensed tremor. The circuitry unit maybe configured to apply the current in phase or out of phase with thetremor. For example, circuitry unit 22 may be configured to drive thecurrent only during particular phases of the tremor (e.g., during ahighest speed portion of the tremor, or, alternatively, only when thelimb is at one or both of the endpoints of its tremor-induced travel).That is, the circuitry unit may be configured to modulate the currentonto the tremor. Alternatively or additionally, the circuitry unit maybe configured to change one or more parameters of the current duringparticular phases of the tremor.

For some applications of the invention, accelerometer 122 is used toadjust timing (e.g., phasing) and/or other parameters of the current, soas to optimize treatment of the tremor. For example, circuitry unit 22may automatically adjust the phase(s) of the tremor during which itdrives the current (i.e., the “angle of phase” at which it drives thecurrent), until optimal treatment is achieved, e.g., by “sweeping”different angles of phase. Similarly, other current parameters, such asfrequency and amplitude, may be optimized automatically by circuitryunit 22.

For some applications of the invention, an extracorporeal device, e.g.,a worn extracorporeal device, comprises an accelerometer, and isconfigured and/or positioned to detect the tremor, and circuitry unit 22of the implant is configured to drive the current in response to theextracorporeal device detecting the tremor. For example, awristwatch-based extracorporeal device may be worn on an arm of thesubject. The wristwatch-based extracorporeal device comprises anaccelerometer and, in response to detecting the tremor in the arm of thesubject, transmits wireless power. The implant receives the wirelesspower and, in response to the wireless power (e.g., powered by thewireless power), drives the current into the arm of the subject (e.g.,into the skin thereof). For such applications, the implant typicallydoes not comprise a power supply. For applications in which a wornextracorporeal device comprises an accelerometer, the implant typicallydoes not comprise an accelerometer.

For some applications, circuitry unit 22 is configurable (e.g., manuallyconfigurable) using an extracorporeal device, such that an operator mayadjust parameters such as phase angle, frequency and amplitude of thecurrent.

For some applications of the invention, tremor in one limb may betreated by an implant implanted in a contralateral limb. For example,tremor in only one limb may be treated by an implant implanted in acontralateral limb, or tremor in a pair of limbs may be treated by animplant implanted in only one of the pair of limbs (i.e., a limb that iscontralateral to at least one of the limbs that experiences the tremor).

Reference is made to FIGS. 14A-C, which are schematic illustrations of asystem 200 for applying a treatment to a tissue of a subject, inaccordance with some applications of the invention. System 200 comprisesa plurality of implants 202 (e.g., implants 202 a, 202 b, 202 c and 202d), and a transmitting unit 210. Transmitting unit 210 transmits atleast one wireless control signal 212, and each implant comprises one ormore effector elements 204, which apply the treatment in response tocontrol signal 212. That is, the each implant is “activated” in responseto the control signal. System 200 is typically configured such that atleast one of the implants applies the treatment asynchronously to atleast another one of the implants. It is noted that in this patentapplication, including the specification and claims, “asynchronous”means “not starting at the same time,” and does not necessarily indicatea lack of coordination and/or synchronization. For example, two implantsthat are configured such that one regularly applies treatment 100 msafter the other, may be synchronized, but apply the treatmentasynchronously.

Transmitting unit 210 is typically extracorporeal. For example, thetransmitting unit may be couplable to a part of the body of the subject,may be wearable by the subject, and/or may be disposed in an item offurniture on which the subject frequently rests, such as a bed ormattress.

Typically, each implant 202 comprises a receiver 206, configured toreceive at least one of the wireless signals transmitted by transmittingunit 210, and a circuitry unit 208, which, at least in part responsivelyto the receiver receiving the wireless signal, drives effector elements204 to apply the treatment. Typically, effector elements 204 compriseelectrodes 205, and circuitry unit 208 drives a current via theelectrodes, at least in part responsively to receiver 206 receivingsignal 212. That is, the treatment typically comprises the delivery ofthe current.

FIG. 14B shows a technique by which system 200 may be configured suchthat at least one of the implants applies the treatment asynchronouslyto at least another one of the implants, in accordance with someapplications of the invention. At least one of the implants 202 isconfigured to apply a treatment 216 after a duration (e.g., a delay) 218following receiving signal 212 that is different from a durationfollowing receiving the signal after which at least another one of theimplants is configured to apply the treatment. For example, and as shownin FIG. 14B, transmitting unit 210 may be configured to transmit onecontrol signal 212 (e.g., a pulse), all the implants (e.g., implants 202a, 202 b, 202 c, and 202 d) receive the signal effectivelysimultaneously, and each implant is configured to apply the treatmentafter a respective different duration (e.g., durations 218 a, 218 b, 218c, and 218 d, respectively) following receiving the signal.

Typically, duration 218 of each implant is pre-set (e.g., circuitry unit208 of each implant is pre-configured thus). For some applications, theduration may be set and/or altered following implantation of implants202, e.g., so as to optimize the application of the treatment. Forexample, duration 218 may be altered wirelessly by an operator, such asa physician who is monitoring the efficacy of the treatment.Alternatively or additionally, duration 218 may be automatically alteredby system 200, using feedback from sensors that monitor thephysiological changes caused by the treatment (not shown).

For the applications of the invention described with reference to FIG.14B, the timing of the activation of the individual implants withrespect to the timing of signal 212 is thereby coordinated predominantlyby the implants themselves. Typically, the implants are activatedsequentially, and the sequential activation may be described as anactivation “wave.” Thereby, for applications of the invention describedwith reference to FIG. 14B, the activation wave is initiated by controlsignal 212 from transmitting unit 210, but is internally coordinatedpredominantly by implants 202.

FIG. 14C shows another technique by which system 200 may be configuredsuch that at least one of the implants applies the treatmentasynchronously to at least another one of the implants, in accordancewith some applications of the invention. Transmitting unit 210 isconfigured to transmit a plurality of control signals 212 (e.g., controlsignals 212 a, 212 b, 212 c, and 212 d), and to transmit at least one ofthe signals asynchronously to another one of the signals, and eachimplant is configured to receive a respective signal. For example, andas shown in FIG. 14C, transmitting unit 210 is configured to transmiteach control signal 212 after a respective different duration (e.g.,durations 218 a, 218 b, 218 c, and 218 d), and each implant, beingconfigured to receive a respective control signal 212, applies treatment216 while receiving the respective signal (e.g., effectively immediatelyupon receiving the respective signal).

For the applications of the invention described with reference to FIG.14C, the timing of the activation of the individual implants is therebycoordinated predominantly by transmitting unit 210. For someapplications, the implants are activated sequentially, and thesequential activation may be described as an activation “wave.” Thereby,for applications of the invention described with reference to FIG. 14C,the activation wave is initiated and coordinated by transmitting unit210. Alternatively, the implants are not activated sequentially. Forexample, the implants may be configured, implanted and/or controlled totreat independent tissues and/or conditions.

Each of the plurality of control signals (e.g., control signals 212 a,212 b, 212 c, and 212 d) typically have an identifying feature thatfacilitates each implant to respond to a respective signals. That is,control signals 212 a-d are typically “coded” (i.e., each signalincludes a respective code), and each implant is configured to respondto a signal that includes a specific code. For example, implant 202 a(e.g., circuitry unit 208 thereof) may be configured to drive a currentthrough electrodes 205 in response to receiving control signal 212 a,but not in response to any of control signals 212 b, 212 c, or 212 d.For some applications, one or more of the implants are each configuredto respond to more than one control signal, i.e., such that one signalactivates more than one implant.

Reference is still made to FIGS. 14A-C. Typically, implants 202 do notcomprise a power supply, such as a battery, that is able to continuouslypower the implants for a period greater than one minute (although theimplants may comprise a temporary power storage element, such as acapacitor). Typically, transmitting unit 210 transmits at least onewireless power signal 214, and implants 202 are wirelessly powered bythe power signal. For example, the power signal may comprise anelectromagnetic signal, such as an RF signal, and each implant 202comprises a rectifying antenna (“rectenna”). Alternatively oradditionally, the power signal may comprise a magnetic signal, and theimplants are powered by electromagnetic induction.

For some applications, power signal 214 is only transmitted at generallythe same time as control signal(s) 212. For the applications of theinvention described with reference to FIG. 14C, power is typically onlytransmitted generally at the same time as each control signal istransmitted (e.g. the power and control signals may comprise the samesignal, such as a coded power signal).

For some applications of the invention, power signal 214 is transmittedat times when signals 212 are not transmitted. For example, power signal214 may be transmitted both at generally the same time as controlsignal(s) 212, and at at least some times when signals 212 are nottransmitted. For the applications of the invention described withreference to FIG. 14B, transmitting unit 210 typically begins totransmit power signal 214 generally at the same time as the unittransmits signal 212, and continues to transmit the power signal for asubsequent duration, such as until all implants 202 have responded tosignal 212. That is, transmitting unit 210 typically transmits powersignal 214 for a duration that is at least as long as duration 218 d.Alternatively, transmitting unit 210 only transmits power signal 214generally at the same time as control signal 212, and each implantcomprises a temporary power storage element, such as a capacitor,capable of storing the power received from signal 214 until the implantapplies the treatment (e.g., capable of storing the power for arespective duration 218).

For some applications, control signals 212 are modulated onto powersignal 214 (e.g., by amplitude and/or frequency modulation). Forexample, with reference to FIG. 14C, power signal 214 may be transmittedfor a duration which is at least as long as duration 218, and controlsignals 212 a-d are modulated onto the power signal. For someapplications, signals 212 and 214 may comprise the same signal (e.g.,the power signal may be a coded power signal). For example, each implantmay be configured to receive and/or be powered by a respective powersignal having a respective characteristic, such as a respectivefrequency, and transmitting unit 210 is configured to activate eachimplant by transmitting the respective power signal.

For some applications, signals 212 and 214 comprise different signals.For example, the signals may be RF signals of different frequencies, orcontrol signal 212 may be an RF signal whilst power signal 214 is amagnetic signal. For some applications, power signal 214 is nottransmitted by transmitting unit 210. For example, power signal 214 maybe provided by a separate power-transmitting unit (not shown). For someapplications, implants 202 do comprise a power supply, such as abattery, that is able to continuously power the implants for a periodgreater than one minute. For such applications, implants 202 aretypically wirelessly rechargeable.

Reference is still made to FIGS. 14A-C. Although system 200 is generallydescribed as being typically configured to facilitate asynchronousapplication of the treatment by each implant, for some applications ofthe invention, system 200 is configured to facilitate generallyindependent control of each implant by the transmitting unit, which mayinclude optionally driving two or more of the implants to apply thetreatment simultaneously. For example, for some applications of theinvention, transmitting unit 210 may be configured to drive a firstactivation “wave” in a first direction, by activating two electrodes ata time along the length of a stimulated tissue, and to subsequentlydrive a second activation wave in the opposite direction. Alternativelyor additionally, one or more implants may be driven to apply thetreatment for an extended duration, during which at least one otherimplant is activated and deactivated (e.g., repeatedly). It is to benoted that these examples are purely illustrative of independent implantcontrol via wireless power transmission, and that the scope of theinvention includes other sequences of implant activation.

Reference is made to FIG. 15, which is a schematic illustration of asystem 220, for applying a treatment to sequential portions of a tubularanatomical structure 226 (e.g., a tubular organ) of a subject, inaccordance with some applications of the invention. Structure 226 maycomprise a hollow tubular structure such as a blood vessel or a part ofthe gastrointestinal tract (e.g., an intestine) of the subject, or maycomprise a more solid tubular structure such as a nerve of the subject.System 220 comprises a plurality of implants 222 (e.g., implants 222 a,222 b, 222 c, and 222 d), and transmitting unit 210. For someapplications of the invention, system 220 and implants 222 are analogousto system 200 and implants 202, described hereinabove with reference toFIGS. 14A-C. Each implant 222 comprises one or more effector elements224, which apply a treatment in response to control signal 212,transmitted by transmitting unit 210. System 220 is configured such thatat least one of the implants applies the treatment asynchronously to atleast another one of the implants.

Typically, system 220 is configured such that each implant 222 isimplanted at a pre-selected distance from at least another implant.Typically, system 220 comprises a support 228 that is configured tofacilitate such implantation, e.g., to facilitate simultaneous deliveryof all the implants and/or to retain the implants 222 at a pre-selectedspacing. FIG. 15 shows structure 226 comprising a hollow tubularstructure of the subject, and support 228 comprising a stent to whichimplants 222 are coupled, and which is typically transluminallydelivered to the lumen of the structure. Alternatively, structure 226may comprise a nerve, and support 228 comprises a nerve cuff that isdisposable around the nerve. Further alternatively, support 228 maycomprise a removable support, such as part of a delivery device, e.g.,that is decoupled from implants 222 following implantation of theimplants. Further alternatively, support 228 may comprise anyimplantable medical device, such as an orthopedic device (e.g., a bonescrew), or a device configured to be placed near the spinal cord.

Effector elements 224 typically comprise electrodes 205. Implants 222are implanted such that electrodes 205 are in electrical contact withstructure 226 (e.g., disposed against the structure). For example,support 228 is pressed against the structure. For some applications,electrodes 205 comprise ring electrodes, and implants 222 are coupled tostructure 226 such that the ring electrodes are disposed over a portionof the structure. Each implant 222 applies the treatment at the portionof structure 226 to which it is coupled, by driving a current viaelectrodes 205, into the portion of the structure. For someapplications, when structure 226 comprises a nerve, the current isconfigured to induce at least one action potential in the nerve. Forsome applications, when structure 226 comprises a hollow tubularstructure, such as a blood vessel or intestine, the current isconfigured to induce constriction in at least the portion of structure226 to which the electrode is in contact.

For some applications, when structure 226 comprises a hollow tubularstructure, effector element 224 comprises an annular constrictingelement that is couplable to a respective portion of the structure, andcircuitry unit 208 of implant 222 is configured to drive theconstricting element to constrict, thereby inducing constriction of theportion of the structure.

For some applications of the invention, system 220 is configured suchthat at least one of the implants applies the treatment asynchronouslyto at least another one of the implants, using techniques described withreference to FIG. 14B, mutatis mutandis. For example, transmitting unit210 may be configured to transmit one control signal 212, all theimplants (e.g., implants 222 a, 222 b, 222 c, and 222 d) receive thesignal effectively simultaneously, and each implant is configured toapply the treatment after a different (e.g., pre-set) duration followingreceiving the signal.

For some applications of the invention, system 220 is configured suchthat at least one of the implants applies the treatment asynchronouslyto at least another one of the implants, using techniques described withreference to FIG. 14C, mutatis mutandis. For example, transmitting unit210 may be configured to transmit a plurality of control signals 212,and to transmit at least one of the control signals asynchronously toanother one of the control signals, and each implant is configured toreceive a respective control signal and to responsively (e.g.,immediately) apply the treatment in the portion of structure 226 towhich it are coupled.

When system 220 is configured to induce constriction in portions of atubular anatomical structure such as a blood vessel or intestine, system220 is typically configured to induce pumping in the structure.Typically, system 220 is configured this way by being configured suchthat implants 222 induce constriction (i.e., are activated)consecutively according to the order in which they are disposed onstructure 226, thereby inducing an advanced form of peristaltic pumping.For example, consecutive activation of implants 222 a, 222 b, 222 c, and222 d may induce peristalsis in structure 226.

For some applications of the invention, structure 226 comprises a bloodvessel of the subject, and system 220 is used to alter blood flow in theblood vessel. For example, structure 226 may comprise the aorta of thesubject, and system 220 may be used to enhance downstream bloodflow inthe aorta by inducing downstream peristalsis (e.g., to treat peripheralvascular disease) and/or to increase blood flow into the coronaryarteries by inducing upstream peristalsis (e.g., during ventriculardiastole).

For some applications of the invention, structure 226 is a component ofthe gastrointestinal tract, such as an intestine or an esophagus, andsystem 220 may be used to induce peristalsis or tighten a sphincter orvalve in the component of the gastrointestinal tract. For example,system 220 may be used to induce peristalsis in an esophagus of thesubject or tighten the lower esophageal sphincter, so as to treatgastroesophageal reflux disease. Alternatively or additionally, system220 may be used to induce peristalsis in a duodenum of the subject, soas to treat obesity.

For some applications of the invention, pumping is induced bystimulating one or more skeletal muscles in a vicinity of a bloodvessel, e.g., so as to compress the blood vessel. Typically, suchpumping is induced by stimulating two or more skeletal muscles tocontract. For some such applications of the invention, system 200 isused, rather than system 220.

Reference is still made to FIGS. 14A-15. As described hereinabove,systems 200 and 220 are configured such that at least implant appliesthe treatment asynchronously to at least another implant. Typically, thesystems are thus configured by being configured such that a state of atleast one of the implants changes asynchronously to the state of atleast another one of the implants. For example, the implants may eachhave an “activated” state, in which the treatment is applied and/orconstriction is induced, and an “off” state, in which that treatment isnot applied and/or constriction is not induced. For some applications ofthe invention, the implants may have one or more other states, such as a“ready” state, and be configured to enter the “ready” state in responseto one or more signals from the transmitting unit. For example (see FIG.14C), when transmitting unit 210 transmits control signal 212 a, andimplant 202 a responsively applies the treatment (i.e., enters the“activated” state thereof), implant 202 b may be configured to enter the“ready” state thereof (e.g., to charge a capacitor thereof) in responseto control signal 212 a, thereby becoming ready to apply the treatmentwhen control signal 212 b is received. It is hypothesized that suchconfiguration reduces a response time of each implant to the controlsignal.

Reference is made to FIG. 16, which is a schematic illustration of asystem 240, for applying a treatment to a plurality of tissues of asubject, in accordance with some applications of the invention. System240 comprises a plurality of implants 242 (e.g., implants 242 a and 242b), and one or more transmitting units 210 (e.g., transmitting units 210a and 210 b). For some applications of the invention, implants 242 a and242 b are similar to each other and are configured to apply similartreatments, e.g., to bilateral tissues, such as opposing limbs, such aslegs 246 (e.g., leg 246 a and 246 b) of the subject. For someapplications, implants 242 are implanted, and configured, to treatneuropathic leg pain. Alternatively, implants 242 a and 242 b areconfigured to treat different conditions and/or to apply differenttreatments.

Typically, transmitting units 210 a and 210 b and/or implants 242 a and242 b are disposed, at least some of the time, in close proximity toeach other (e.g., within 1 m of each other, such as within 30 cm of eachother, such as within 10 cm of each other). For example, and as shown inFIG. 16, a first transmitting unit 210 a is coupled (e.g., adheredand/or strapped) to a first leg of a subject, and intended (e.g.,configured) to power and control a first implant 242 a, and a secondtransmitting unit 210 b is coupled to a second leg of the subject, andintended (e.g., configured) to control a second implant 242 b.

The use of one or more transmitting units to control a plurality ofimplants may be subjected to problems, such as interference and/ormisdirected signals. That is, a first implant may receive, and respondto, a signal that is intended to be received by a second implant. Thisis more likely when the transmitting units and implants are in closeproximity to each other. For example, implant 242 b might respond tosignals transmitted by unit 210 a, and/or implant 242 a might respond tosignals transmitted by unit 210 b.

Typically, apparatus 240 is configured to use coded signals, e.g., asdescribed hereinabove with reference to FIGS. 14A-15. For example,transmitting unit 210 a may be configured to transmit wireless power ata first frequency, which implant 242 a is configured to receive and/orby which implant 242 a is configured be powered; while transmitting unit210 b is configured to transmit wireless power at a second frequency,which implant 242 b is configured to receive and/or by which implant 242b is configured to be powered. Alternatively or additionally, first andsecond pulse widths may be used to “code” the signals. Alternatively oradditionally, first and second on-off patterns (i.e., durations forwhich the wireless power is transmitted and not transmitted) may be usedto “code” the signals. It is hypothesized that the use of coded signalsreduces (e.g., prevents) misdirected signals when wirelessly controllinga plurality of implants, and especially implants that are in closeproximity. Such misdirected signals may interfere with treatment and/orcause the subject discomfort and/or pain.

For some applications of the invention, transmitting units 210 a and 210b are configured to be in wireless communication with each other. Forexample, it may be desirable for the transmitting units to coordinatethe driving of implant 242 b with respect to the driving of implant 242a. For example, transmitting unit 210 b may be configured to driveimplant 242 b only when transmitting unit 210 a is not driving implant242 a (i.e., asynchronously). Alternatively, transmitting unit 210 b maybe configured to drive implant 242 b at the same time as transmittingunit 210 a drives implant 242 a. It is to be noted that these twoexamples are illustrative, and that the scope of the invention includesany coordination between transmitting units 210 a and 210 b for drivingimplants 242 a and 242 b.

Reference is again made to FIGS. 14A-16. For some applications of theinvention, asynchronous application of treatment comprises coordinatedapplication of treatment. For example, the system may be configured toprovide a “wave” of stimulation, such as to induce peristalsis (e.g., asdescribed with reference to FIG. 15). Alternatively, for someapplications of the invention, asynchronous application of treatmentcomprises independent application of one or more treatments. Forexample, the system may be configured to provide two different andindependent treatments using two different implants that are controlledby the same transmitting unit. It is to be noted that the techniques forcontrolling multiple implants, described with reference to FIGS. 14A-16may be combined with other techniques and other implants, such as thosedescribed with reference to FIGS. 1-13, mutatis mutandis.

Reference is made to FIGS. 17A-E, which are schematic illustrations ofantenna 30, in accordance with respective applications of the invention.Hereinabove, antenna 30 is illustrated as a coiled antenna purely as anexample. Further, non-limiting examples of embodiments of antenna 30,for use with one or more of the implants described hereinabove, aredescribed with reference to FIGS. 17A-E. FIG. 17A shows antenna 30,comprising an antenna 250, which comprises a coil 252 disposed around aferrite core 254. FIG. 17B shows antenna 30 comprising an antenna 260,which comprises two mutually-perpendicular coils 252. FIG. 17C showsantenna 30 comprising an antenna 270, which comprises threemutually-perpendicular coils 252. It is hypothesized thatmutually-perpendicular coils facilitate reception of wireless powerand/or other signals, e.g., independently of an orientation of theimplant. For some applications, antenna 260 and/or antenna 270 compriseat least one ferrite core 254, as described with reference to FIG. 17A,mutatis mutandis. For example, each coil 252 of antenna 260 and/or 270may be disposed around a ferrite core 254.

FIG. 17D shows antenna 30 comprising a planar spiral antenna 280.Antenna 280 is shown as a square spiral, but may be a round spiral, orany other spiral.

FIG. 17E shows antenna 30 comprising a helical antenna 290. Antenna 290is shown as a cuboid helix, but may be a cylindrical helix, or any otherhelix. It is hypothesized that a helical antenna facilitateseconomization of space, by other components (e.g., circuitry units 22and/or 208) being disposable within a void 292, defined by the helix ofthe antenna.

Reference is again made to FIGS. 1-17E. For some applications of theinvention, the implants described hereinabove may comprise effectorelements other than electrodes (e.g., the effector elements describedhereinabove may comprise other components, and/or the electrodesdescribed hereinabove may be replaced with other effector elements). Forexample, for some applications of the invention, one or more of theeffector elements may comprise a vibrating element, and the treatment isapplied by the circuitry unit driving the vibrating element to vibrate.This vibrating element may be employed in addition to or instead of anyor all of the electrodes (e.g., electrodes 28) described herein, withreference to FIGS. 1-17E. It is hypothesized that, for someapplications, vibrational stimulation is useful for stimulating sensoryfibers. For example, an implant, implanted subcutaneously as describedwith reference to FIG. 13, may be used to vibrationally stimulatesensory fibers in the skin of the subject.

For some applications, a combination of electrodes and vibrating unitsis used in the same implant and/or in different implants. It is notedwith reference to FIGS. 11 and 12 that insulating member 136 may bemechanically insulating in order to reduce passage of vibrations intodeeper tissues, and to instead maintain more of the vibrational energynear the sensory fibers in the skin of the subject. For suchapplications, this mechanically-insulating member typically acts as aninhibiting element that inhibits direct stimulation of one or moredeeper nerves.

Similarly, one or more of the effector elements described hereinabovemay comprise a heating and/or cooling element, a pressure-exertingelement, an ultrasound transducer, and/or a laser. Alternatively oradditionally, one or more of the implants described hereinabove maycomprise one or more sensors, e.g., to provide feedback.

The implantation sites and disorders described hereinabove are examplesfor illustrating the use of the techniques described herein. Theimplants described herein may be implanted at a variety of implantationsites, and the techniques described herein may be used to treat avariety of disorders. For example:

-   -   stimulation of the tibial nerve (and/or of sensory fibers that        lead to the tibial nerve), e.g., to treat neuropathic pain        and/or urge incontinence;    -   stimulation of sensory fibers that lead to the radial and/or        ulnar nerves, e.g., to treat tremor (e.g., essential tremor, and        tremor associated with Parkinson's disease);    -   stimulation of the occipital nerve, e.g., to treat migraine;    -   stimulation of the sphenopalatine ganglion, e.g., to treat        cluster headaches;    -   stimulation of the sacral and/or pudendal nerve, e.g., to treat        urge incontinence;    -   direct stimulation of an implantation site within the brain        (e.g., deep brain stimulation), such as the thalamus, e.g., to        treat tremor, obsessive-compulsive disorder, and/or depression;    -   stimulation of the vagus nerve, e.g., to treat epilepsy,        depression, inflammation, tinnitus, and/or congestive heart        failure (e.g., by incorporating some or all of device 20 into an        aortic stent);    -   stimulation of baroreceptors in a blood vessel wall (e.g., the        wall of the carotid sinus and/or aorta, e.g., to treat high        blood pressure);    -   stimulation of the spinal cord, e.g., to treat pain;    -   stimulation of one or more muscles (such as shoulder muscles),        e.g., to treat muscle pain;    -   stimulation of the medial nerve, e.g., to treat carpal tunnel        syndrome;    -   stimulation of the hypoglossal nerve and/or one or more muscles        of the tongue, e.g., to treat obstructive sleep apnea;    -   stimulation of cardiac tissue, e.g., to pace and/or defibrillate        the heart (e.g., the use of the implant as a leadless        pacemaker);    -   stimulation to treat dystonia;    -   stimulation of the vagus nerve, e.g., to treat epilepsy;    -   stimulation to treat interstitial cystitis;    -   stimulation to treat gastroparesis;    -   stimulation to treat obesity;    -   stimulation of the anal sphincter, e.g., to treat fecal        incontinence;    -   stimulation to treat bowel disorders;    -   stimulation of peripheral nerves of the spinal cord, e.g., to        treat chronic pain;    -   stimulation of the dorsal root ganglion for the treatment of        chronic pain; and    -   stimulation of motor nerves and/or muscles to improve mobility.

Implants whose effector element comprises an electrode and/or avibrating element may also be used to block nerve signals, such as toinduce local anesthesia. It is hypothesized that paresthesia may beinduced by driving a relatively low-frequency current (e.g., greaterthan 1 and/or less than 120 Hz, e.g., between 10 and 40 Hz) into thenerve, and that a relatively high-frequency current (e.g., greater than5 and/or less than 20 kHz, e.g., between 10 and 20 kHz) may be used toinduce complete blocking.

Tibial nerve stimulation (e.g., electrical stimulation) may be used totreat pain, such as neuropathic pain, e.g., neuropathic pain in the legsof a subject. Implants, such as those described hereinabove, may be usedto provide such stimulation. However, variation between subjects exists,and such treatment does not sufficiently reduce pain in all subjects. Inexperiments conducted by the inventors, percutaneous electrodes (i.e.,temporary electrodes) were used to stimulate the tibial nerve of 8subjects by percutaneously delivering at least part (e.g., a tip) of theelectrodes to a site in a vicinity of the tibial nerve, and applying acurrent to the tibial nerve. Sessions comprised 15-60 minutes ofstimulation. Of these 8 subjects, 6 experienced good pain relief and 2experienced moderate pain relief. Interestingly, the degree of painrelief for each subject in the first session was similar to that for thesuccessive sessions. That is, a first session of stimulation wasindicative of responsiveness to subsequent treatment. It is thereforehypothesized that data from a single session of percutaneous stimulationof the tibial nerve, lasting 1-120 minutes (e.g., 10-30 minutes) ofstimulation and successfully inducing paresthesia in the subject's foot,may be used to facilitate a decision of whether to implant one or morestimulatory implants at the tibial nerve of a given subject.

It will be appreciated by persons skilled in the art that the presentinvention is not limited to what has been particularly shown anddescribed hereinabove. Rather, the scope of the present inventionincludes both combinations and subcombinations of the various featuresdescribed hereinabove, as well as variations and modifications thereofthat are not in the prior art, which would occur to persons skilled inthe art upon reading the foregoing description.

1-146. (canceled)
 147. A method for treating a condition of a subject, the method comprising: placing an implant into a tissue of the subject, the implant including: a circuitry unit, the circuitry unit: housing circuitry, and shaped to define a height, the height being smaller than (i) a longest length, and (ii) a longest width of the circuitry unit; and one or more outwardly-facing electrodes that are electrically coupled to the circuitry; and orienting the implant with respect to the tissue, such that: (a) the height of the circuitry unit is disposed along a superficial-to-deep axis with respect to skin of the subject, (b) the implant is positioned to stimulate a nerve underlying the implant, and (c) the implant is positioned in a manner that inhibits electrical conduction from the outwardly-facing electrodes into skin of the subject.
 148. The method according to claim 147, wherein each of the outwardly-facing electrodes extend around an arced portion of the implant.
 149. The method according to claim 147, wherein the step of implanting comprises injecting the implant into the tissue of the subject.
 150. The method according to claim 147, wherein: the circuitry unit is shaped to define a prismatic shape, and the step of implanting comprises implanting the implant into the tissue such that the prismatic shape of the circuitry unit is generally parallel with a plane defined by a skin surface of the subject.
 151. The method according to claim 147, wherein the implant includes a generally flat inhibiting element, the inhibiting element configured to inhibit electrical conduction therethrough.
 152. The method according to claim 147, wherein: the implant includes an inhibiting element, the inhibiting element configured to inhibit electrical conduction therethrough, and the step of implanting comprises implanting the implant into the tissue of the subject, such that the inhibiting element inhibits electrical conduction from the electrodes into tissue that is superficial to the implant.
 153. The method according to claim 147, wherein: the height of the circuitry unit is between 0.5 and 3 mm, the longest width of the circuitry unit is between 1 and 5 mm, and the longest length of the circuitry unit is between 5 and 30 mm.
 154. The method according to claim 147, wherein: the one or more outwardly-facing electrodes include a pair of electrodes that are disposed at a distance of less than 10 mm from each other, and the method further comprises, using the circuitry unit, driving current through the electrodes and to the nerve.
 155. The method according to claim 154, wherein the pair of electrodes are disposed at a distance of less than 2 mm from each other.
 156. The method according to claim 154, wherein driving current comprises driving current through the electrodes and to a tibial nerve of the subject to treat a condition selected from the group consisting of: neuropathic pain, and urge incontinence.
 157. The method according to claim 154, wherein: the step of using the circuitry unit comprises, using a transmitting unit, transmitting a control signal that activates the circuitry unit to drive current through the electrodes and to the nerve.
 158. The method according to claim 147, wherein the height of the circuitry unit is less than 3 mm.
 159. The method according to claim 158, wherein the height of the circuitry unit is between 0.5 and 3 mm.
 160. The method according to claim 159, wherein the height of the circuitry unit is between 1.5 and 2 mm.
 161. The method according to claim 147, wherein the longest width of the circuitry unit is less than 5 mm.
 162. The method according to claim 161, wherein the longest width of the circuitry unit is between 1 and 5 mm.
 163. The method according to claim 147, wherein the longest length of the circuitry unit is less than 30 mm.
 164. The method according to claim 163, wherein the longest length of the circuitry unit is between 5 and 30 mm.
 165. The method according to claim 164, wherein the longest length of the circuitry unit is between 10 and 30 mm. 